1. Technical Field
This invention relates generally to vegetation trimmers and more particularly to a power driven remotely controlled trimmer unit mountable on a boom carried by a motorized mobile vehicle for trimming on flat surfaces, on inclined surfaces, as well as around immovable objects such as posts, trees, stones and the like removably mounted to a motorized mobile vehicle having such trimmer mounted thereon. More particularly, the invention includes a line trimmer including a novel controlled line feed for trimmers.
2. Description of the Prior Art
Line trimmers are well known some of which are hand carried while other larger units are mounted on a motorized vehicle. Vehicle carried vegetation trimmers are disclosed in the following Unites States Patents: U.S. Pat. No. 5,704,201 granted Jan. 6, 1998 to R. Van Vleet; U.S. Pat. No. 5,396,754 granted Mar. 14, 1995 to J. Fraley; U.S. Pat. No. 5,050,372 granted Sep. 24, 1991 to M. Heiskell; U.S. Pat. No. 5,040,360 granted Aug. 20, 1991 to J. Meehieder; U.S. Pat. No. 4,996,830 granted Mar. 5, 1991 to T. Davison; U.S. Pat. No. 4,901,508 granted Feb. 20, 1990 to D. Whatley; U.S. Pat. No. 4,873,818 granted Oct. 17, 1989 to A. Turner; U.S. Pat. No. 4,802,327 granted Feb. 7, 1989 to C. Roberts; and U.S. Pat. No. 3,729,910 granted May 1, 1973 to E. Hardee.
It is known from the foregoing to mount the cutting unit on the vehicle by attaching it to a three point hitch as taught in U.S. Pat. No. 5,050,372, by a linkage system as taught in U.S. Pat. No. 5,704,201, or by a boom as taught in U.S. Pat. No. 5,396,754.
The prior art devices generally require a lot of operator manipulation of the vehicle and/or the cutter assembly mounted thereon and in many cases cannot even attempt to perform the task.
The present apparatus overcomes some operator manipulation requirements and other problems associated with the prior art devices by having a cutter head mounted on an open frame and mounted thereon by linkage means whereby it is moveable relative thereto against a spring bias. The frame is preferrably generally xe2x80x98Uxe2x80x99 or xe2x80x98Vxe2x80x99 shaped (but need not be so) and the cutter head is located in the open bite portion of the xe2x80x98Uxe2x80x99. The cutter head maybe supported on the ground by caster wheels and pivotally attached in such a manner as to allow it to follow the land surface contour. The cutter maybe a blade (or blades) that maybe rigid, or yieldable when striking an immovable object and it maybe surrounded by an annular guard fixedly secured to the cutter support.
The instant invention provides a vegetation trimmer unit having an open generally xe2x80x98Uxe2x80x99-shape frame with a power driven string line cutter mounted thereon by a linkage mechanism that permits the cutter head to move to the frame against a spring biasing the cutter head in reaction outwardly away from the frame. The unit is suspendable ram the free outer end of an extendible and retractable vehicle mounted boom. An actuator located on the vehicle is use to dispense sequentially predetermined lengths of line from the string line cutter.
Moreover the invention is a mountable trimmer unit, attachable to the free end of a vehicle mounted boom. A rigid frame having means on the underside thereof such as one or more wheels, rollers, runners, or floating balls, for glidingly supporting the trimmer unit on the surface of the ground at a selected level. A cutter head having a power driven vegetation cutter such as a string trimmer extends therefrom. Linkage means connected to the frame and the cutter head are used to mount the cutter unit on the frame for movement relative thereto and allow the cutter head to be pivoted at an angle in the horizontal plane. Means carried by the frame such as hydraulic units, electric solenoids, air operated solenoids, or mechanical devices such as cams and springs are connected to the cutter head control the movement of the cutter unit relative to the frame.
The cutter head mounting linkage means has springs attached thereto such that the cutter head is biased to an extended or forward at rest position. A cutter element guard, carried by the cutter head, strikes an object when the trimming unit is moving and moves the cutter head, relative to the frame, against the pressure exerted by the springs. Moreover, the cutter head and optionally the cutter guard extend outwardly past the frame whereby up to 50% of the rotary cutter head projects past the frame in order to permit close trimming of vegetation around obstacles. As the trimming unit continues moving the cutter head is deflected by the obstacle toward the web portion of the xe2x80x98Uxe2x80x99 shape frame. The spring bias returns the cutter head to its original at rest position when the cutter head has passed by the obstacle. The cutter head is further movably mounted by being pivoted for movement about a horizontal axis so that it can be controllably tilted to cut on an incline or decline.
The cutting element guard is a wheel like member journaled on the cutter head and thus is able to roll on the outer peripheral surface of a tree trunk, a vertical post or the like causing the cutter head to move laterally around the immovable object while the cutter element trims the vegetation around such object.
The frame, on which the cutter head is mounted, is controllably rotatable about a vertical axis with such operation being controlled by the operator.
Apparatus constructed in accordance with the present invention can incorporate one or more or all of the foregoing features or various combinations or sub-combinations thereof.
A principal object of the present invention is to provide a removable trimmer unit that is mountable on a motorized vehicle and wherein the trimmer unit has a frame with a power driven cutter head movably mounted thereon.
A further object of the present invention is to provide a vegetation trimmer capable of cutting around obstacles with a minimum of operator effort.
A further principal object is to provide a motorized mobile vehicle apparatus for mowing and/or trimming around large fields of grassland such as parks, playgrounds, boulevards, road allowances or the like and which has mounted thereon a power driven trimmer unit capable of cutting around trees, posts, rocks and the like immovable objects and with minium operator manipulation.
Another object of the present invention is to provide a trimming head having at least one me and preferably multiple lines automatically releasable therefrom positioned axially on a spindle.